System.Net.WebException: The request failed with HTTP status 407: Proxy Authentication Required ( The ISA Server requires authorization to fulfill the request. Access to the Web Proxy filter is denied. ).~~ at Microsoft.UpdateServices.Administration.AdminProxy.CreateUpdateServer(Object[] args)~~ at Microsoft.UpdateServices.Administration.AdminProxy.GetUpdateServer(String serverName, Boolean useSecureConnection, Int32 portNumber)~~ at Microsoft.SystemsManagementServer.WSUS.WSUSServer.ConnectToWSUSServer(String ServerName, Boolean UseSSL, Int32 PortNumber)

Solution

Remove following keys from the registry HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections\DefaultConnectionSettings

HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\InternetSettings\Connections\SavedLegacySettings